(()=>{

    class Person{

        firstName:string
        lastName:string

        constructor(firstName:string,lastName:string) {
            this.firstName = firstName
            this.lastName = lastName
        }

        get fullName(){

            return this.firstName +'_'+ this.lastName
        }

        set fullName(val:string){
            let names = val.split('_')
            this.firstName = names[0]
            this.lastName = names[1]
        }

    }

    let p = new Person('东方','不败')
    console.log(p.fullName)
    p.fullName = '诸葛_孔明'

    console.log(p.firstName)
    console.log(p.lastName)
    console.log(p.fullName)

    let a:string = 'aaa'
    let b = a.concat('a','b','c')
    console.log(b)

})()
